Counterbalanced cover arrangement

ABSTRACT

A HOUSING HAVING A COVER THAT MUST BE LIFTED IN ORDER TO OPEN THE HOUSING, AND A SPRING FOR COUNTERBALANCING A PORTION OF THE COVER&#39;&#39;S WEIGHT.

Jan. 19, 1971 T. BQBIALLARDJ 3,555,732 COUNTERBALANCED COVER ARRANGEMENT Original Filed Sept. 22, 1967 FIG-2 INVENTQR THOMAS B. BALLABD vB I z/fanneys United States Patent COUNTERBALAN CED COVER ARRANGEMENT Thomas B. Ballard, 2550 Mulberry Drive, Southfield, Mich. 48075 Original application Sept. 22, 1967, Ser. No. 669,786, now Patent No. 3,452,763. Divided and this application May 8, 1969, Ser. No. 822,989

' Int. Cl. E05f 1/10 US. Cl. 49-386 5 Claims ABSTRACT OF THE DISCLOSURE A housing having a cover that must be lifted in order to open the housing, and a spring for counterbalancing a portion of the covers weight.

CROSS-REFERENCE TO RELATED APPLICATION This application is a division of application Ser. No. 669,786 filed Sept. 22, 1967, now US. Pat. 3,452,763.

BACKGROUND OF THE INVENTION This invention relates to means for counterbalancing the weight of a cover that must be lifted to provide access through an opening.

In my aforementioned co-pending application, a cleaning apparatus was disclosed for removing foreign matter from engine blocks and the like which are received in a housing and then rotated on a turntable while being sprayed by heated cleaning liquids. The cleaning cham- SUMMARY OF THE INVENTION The preferred embodiment of the present invention comprises a spring counterbalance which is connected to bias a relatively heavy cover from a lower, closed position toward a raised, partially open position in order to assist the operator in lifting the cover. Although the cover is pivotal through an arc of about 180 between its fully closed and fully open positions, the spring is so connected that as the cover is lifted from its fully closed position, the bias of the spring is gradually reduced until the cover is substantially upright in its partially open position with its center of gravity above its pivot axis. The spring then acts as a link to hold the cover open without biasing it beyond its raised position.

Although the preferred counterbalance biases the cover through only a portion of its full range of motion, it comprises only an elongated coil spring which has one end attached to the cover, and its other end disposed in a tubular socket mounted on the housing. The connection between the socket and the spring is such as to place the spring in a state of tension only in that portion of the covers path of motion between its fully closed and its raised partially open positions.

In summary, the spring counterbalance assists the operator in lifting the cover to open the housing, holds the cover in its raised position to permit the passage of an engine block or the like through the housing opening and then permits the operator to safely lower the cover without any danger of its full weight falling in an unrestrained manner.

Still further objects and advantages of the invention will become readily apparent to those skilled in the art 3,555,732 Patented Jan. 19, 1971 to which the invention pertains upon reference to the following detailed description.

DESCRIPTION OF THE DRAWINGS The description refers to the accompanying drawing in which like reference characters refer to like parts throughout the several views, and in which:

FIG. 1 is a perspective view of a cleaning apparatus having a counterbalanced cover, illustrating the preferred embodiment of the present invention, shown in its raised, open position; and

FIG. 2 is a view showing the cover in its closed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, the preferred embodiment is incorporated in a cleaning apparatus, generally indicated at 10, which comprises an insulated housing 12 having an internal cleaning chamber 14 for the engine components (not shown) that are to be cleaned. A caustic cleaning solution is circulated through the chamber 14 to remove foreign matter from the engine components which are then rinsed by a solution that is introduced into the chamber 14 at the end of the wash cycle. The rinse solution is discharged through a conduit 16 to a drain 18 in a manner which prevents dilution of the cleaning solution and which is more fully disclosed in my aforementioned pending patent application.

A relatively heavy cover 20 is pivotally connected by hinges 22 to the housing 12 so as to be movable about a horizontal hinge axis between a lower, closed position, illustrated in FIG. 2, in which it blocks access into the chamber 14; a raised, open position in which it allows access into the chamber 14, and a lower, fully open position in which it is pivoted rearwardly beyond its raised position. A pair of spray shields 24 (only one shown) depend from the sides of the cover 20' and extend into the chamber 14 to provide a liquid splash barrier when the cover is open. A handle 26 carried on the front side of the cover 20 provides means for the operator to manually raise or lower the cover.

A pair of supports 28 extend rearwardly from opposite sides of the cover 20. A pair of brackets 30 extend rearwardly of the housing 12, each bracket being disposed beneath a support 28. A coil spring 32 is supported between each support 28 and each bracket 30. Each spring 32 has an upper end connected to the outer end of its support 28, and a lower end telescopically received by a tube 34 which is pivotally mounted on the outer end of each bracket 30. A pair of caps 36, carried on the extreme lower end of the two springs 32, engage the lower end of the tubes whenever the springs are disposed in a state of tension.

Whenever the cover 20 is in its lower, closed position, both springs 32 are extended to urge the cover upwardly toward its open position. However the weight of the cover is such that it remains closed unless it is lifted by the operator. As the operator lifts the cover, a portion of its weight is counterbalanced by the bias of the springs 32. As the cover is raised, both springs gradually become shortened toward their unstressed state. When the cover is disposed in its raised position in which its center of gravity is slightly forward of its hinge axis, the two springs 32 are relatively unstressed and act as a pair of links which prevent the cover from falling toward its closed position. Because of their unstressed condition, the springs do not bias the cover beyond its raised position toward its fully open position. Therefore, the operator can release the handle 26 with the cover remaining in its raised position. If he should lower the cover rearwardly toward its fully open position, the caps 36 drop below the tubes 34 as shown inFIG. 1. As the operator lowers the cover 20 forwardly, the springs 32 are extended to counterbalance a portion of the covers weight and allowthe cover to be safely manipulated.

The springs 32 provide their greatest upward bias when the cover 20 is in its fully closed position. As the cover is raised, the springs are shortened so that their bias varies as the angular displacement of the cover from its raised position. This mounting arrangement provides a special advantage because the torque necessary to raise the cover is greatest in its closed position and decreases as the center of gravity of the cover is moved to a position above its hinge axis. Thus the bias of the springs is substantially proportional to the effort necessary to counterbalance the cover.

It is to be understood that I have described a novel spring counterbalance for assisting an operator in raising and lowering a relatively heavy cover, and for maintaining the cover in a static raised position.

Having described my invention, I claim:

1. A counterbalance assembly for a hinged container cover comprising: a container having an opening, a cover disposed over the opening and pivotal with respect to the container about a rearwardly disposed horizontal axis between open and closed positions, control means including a spring connected between rearwardly disposed portions of the container and cover and having one end se cured to one of said container and cover and the other end slidably disposed relative to the other of the container and cover for providing an unbiased sliding connection therebetween over the portion of the pivotal displacement between the container and cover between fully opened and partially opened positions, the spring including stop means acting on said other of the container and cover such that the spring is placed in tension to oppose displacement of the cover from the partially opehe 'dpdsition to a fully closed position.

2. Apparatus as defined in claim 1 wherein the control means includes a first rigidmember secured to the con-' tainer, a second rigid member secured to the cover, the spring having one end fixed to one of the rigid members and the other end slidably displaceable into contact. with the other of the rigid members at a pivotal displacement of the cover between the open and closed positions.

3. Apparatus as defined in claim 2 wherein the first rigid member is a support arm extending rearwardly of the cover. The second rigid member is a bracket extending rearwardly of the container, said other end of the spring being fixed to the support arm.

4. Apparatus as defined in claim 3 wherein the spring is helical, the apparatus further comprising a tubular member secured to the bracket and axially slidably receiving the spring therein, the stop means being disposed on said other end of the spring for engagement with the tubular member when the cover is between the open and closed positions thereby to extend the spring as the cover is pivotally disposed to the closed position. 7

5. Apparatus as claimed in claim 4 wherein the tubular member is pivotally disposed on the bracket for rotation of about a horizontal axis parallel to the pivotal axis of the cover.

References Cited UNITED STATES PATENTS 1,232,340 7/1917 Lehson 49--386 1,721,308 7/1929 Lormor 49-386X 3,001,227 9/1961 Long et a1 22O35X KENNETH DOWNEY, Primary Examiner U.S. Cl. X.Rt 220-35 

